#include <stdio.h>
#define ROWS 3
#define COLS 4
int sum2d(int, int, int [*][*]);
int main(void)
{
    int i, j;
    int rs = 3, cs = 10;
    int junk[ROWS][COLS] = {{2, 4, 6, 8}, {3, 5, 7, 9}, {12, 10, 8, 6}};
    int morejunk[ROWS -1][COLS + 2] = {{20, 30, 40, 50, 60, 70}, {5, 6, 7 ,8, 9, 10}};
    int varr[rs][cs];
    for(i = 0; i < rs; i++)
        for(j = 0; j < cs; j++)
            varr[i][j] = i * j + j;
    printf("3 x 4 array\n");
    printf("Sum of all elements = %d\n", sum2d(ROWS,COLS,junk));
    printf("2 x 6 array\n");
    printf("Sum of all elements = %d\n", sum2d(ROWS - 1, COLS + 2, morejunk));
    printf("3 x 10 array\n");
    printf("Sum of all elements = %d\n", sum2d(rs, cs, varr));
    return 0;
}

int sum2d(int rows, int cols, int ar[rows][cols])
{
    int r, c;
    int tot = 0;
    for(r = 0; r < rows; r++)
        for(c = 0; c < cols; c++)
            tot +=ar[r][c];
    return tot;
}
